As the use of mobile wireless devices, such as smart phones and tablet devices, becomes more ubiquitous, the demands on the limited amount of radio frequency spectrum used by those devices also increases, resulting in wireless network congestion in the licensed spectrum. In addition, the increased use of high bandwidth applications such as audio and video streaming can increase demands beyond the capability of the available spectrum. This is especially true in high density and high use locations such as large cities and universities. One projection estimates a growth of 20 times in mobile internet traffic from 2010 to 2015.
One way of increasing bandwidth in wireless devices is through the use of carrier aggregation, in which multiple carriers having different frequencies are aggregated to form a virtual wideband connection for a wireless device. However, transmitting and receiving over different frequencies can create a number of challenges. For example, the different carriers may travel different paths between the wireless device and the base station or access point. The distinct propagation paths between different carriers can create timing differences in the reception of the signals. This can be disadvantageous in wireless systems that combine data for multiple devices in a single signal, such as in systems that use Orthogonal Frequency Division Multiple Access (OFDMA).
Reference will now be made to the exemplary embodiments illustrated, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended.